α1β1整合素的过表达直接影响大鼠系膜细胞的行为。

Overexpression of alpha1beta1 integrin directly affects rat mesangial cell behavior.

作者信息

Kagami S, Kondo S, Urushihara M, Löster K, Reutter W, Saijo T, Kitamura A, Kobayashi S, Kuroda Y

机构信息

Department of Pediatrics, School of Medicine, University of Tokushima, Tokushima, Japan, and Institute für Molekularbiologie und Biochemi, Freie Universitat Berlin, Berlin-Dahlem, Germany.

出版信息

Kidney Int. 2000 Sep;58(3):1088-97. doi: 10.1046/j.1523-1755.2000.00266.x.

DOI:10.1046/j.1523-1755.2000.00266.x

PMID:10972673

Abstract

BACKGROUND

Glomerular mesangial cell (MC) proliferation, hypertrophy, and abnormal matrix remodeling characterized by increased expression of fibronectin, laminin and collagen type IV, and neoexpression of collagen I and III are the main biological features of progressive glomerulonephritis (GN). Especially, persistent pathological matrix remodeling may lead to glomerular scar formation (glomerular scarring). We reported recently that alpha1beta1 integrin, a major collagen receptor for MCs, may be a potential adhesion molecule for MC-mediated pathological collagen matrix remodeling in GN.

METHODS

To address further the direct role of alpha1beta1 integrin in MC behavior, such as cell growth and matrix remodeling, alpha1beta1 integrin was overexpressed in MCs by transfecting an expression vector containing a full-length rat alpha1 integrin cDNA. Flow cytometry and immunoprecipitation analysis were applied for selection of transfectants with a stable expression of the alpha1 integrin subunit. The effect of alpha1beta1 integrin overexpression on MC biology was examined with a 3H-thymidine incorporation assay, flow cytometric analysis of cell size and DNA content, Western blot analysis of a cyclin-dependent-kinase inhibitor, p27Kip1, alpha-smooth muscle actin expression, and a collagen gel contraction assay.

RESULTS

The alpha1 transfectants displayed a dramatic inhibition of 3H-thymidine incorporation as compared with the mock transfectants. Increased expression of the alpha1 subunit inversely correlated with cell cycle progression and paralleled the expression of p27Kip1 and alpha-smooth muscle actin, as well as the cell size in MCs. In addition, the alpha1-transfectants were able to enhance collagen matrix reorganization effectively.

CONCLUSION

These results indicate that MC-alpha1beta1 integrin expression is a critical determinant of MC phenotypes, including cell growth, cell size, and collagen matrix remodeling ability, and thereby contributes to scar matrix remodeling (sclerosis) in GN.

摘要

背景

肾小球系膜细胞（MC）增殖、肥大以及以纤连蛋白、层粘连蛋白和IV型胶原表达增加，I型和III型胶原新表达为特征的异常基质重塑是进行性肾小球肾炎（GN）的主要生物学特征。特别是，持续性病理基质重塑可能导致肾小球瘢痕形成（肾小球硬化）。我们最近报道，α1β1整合素是MC的主要胶原受体，可能是GN中MC介导的病理性胶原基质重塑的潜在黏附分子。

方法

为了进一步探讨α1β1整合素在MC行为（如细胞生长和基质重塑）中的直接作用，通过转染包含全长大鼠α1整合素cDNA的表达载体，使α1β1整合素在MC中过表达。应用流式细胞术和免疫沉淀分析筛选稳定表达α1整合素亚基的转染子。用3H-胸腺嘧啶核苷掺入试验、细胞大小和DNA含量的流式细胞术分析、细胞周期蛋白依赖性激酶抑制剂p27Kip1的蛋白质印迹分析、α-平滑肌肌动蛋白表达以及胶原凝胶收缩试验检测α1β1整合素过表达对MC生物学的影响。